My Statistical Consultant Blog

You can re-code an entire vector or array at once. To illustrate, let’s set up a vector that has missing values. A

SPSS has the Count Values within Cases option, but R does not have an equivalent function. Here are two functions that you might find helpful, each of which counts values within cases inside a rectangular array. For example, you might have a dataset consisting of responses to a questionnaire involving…

Test for the existence of particular values using the any() and all() commands Create a vector b: b

Counting elements in a dataset Combining the length() and which() commands gives a handy method of counting elements that meet particular criteria. b <- c(7, 2, 4, 3, -1, -2, 3, 3, 6, 8, 12, 7, 3) b Let’s count the 3s in the vector b. count3 <- length(which(b ==…

In Part 15, we saw how to create a simple Generalised Linear Model on binary data using the glm() command. We continue with the same glm (modelling the vs variable on the weight and engine displacement) on the same data set – the mtcars dataset – which is built into…

In Part 15, let’s see how to create simple Generalised Linear Models in R. Ordinary Least Squares regression provides linear models of continuous variables. However, much data of interest to statisticians and researchers are not continuous and so other methods must be used to create useful predictive models. The glm()…

In Part 14, let’s see how to create pie charts in R. Let’s create a simple pie chart using the pie() command. As always, we set up a vector of numbers and then we plot them. B <- c(2, 4, 5, 7, 12, 14, 16) Create a simple pie chart….

In Part 13, let’s see how to create boxplots in R. Let’s create a simple boxplot using the boxplot() command, which is easy to use. First, we set up a vector of numbers and then we plot them. Boxplots can be created for individual variables or for variables by group….

In Part 12, let’s see how to create histograms in R. Let’s create a simple histogram using the hist() command, which is easy to use, but actually quite sophisticated. First, we set up a vector of numbers and then we create a histogram. B <- c(2, 4, 5, 7, 12,…

In Part 11, let’s see how to create bar charts in R. Let’s create a simple bar chart using the barplot() command, which is easy to use. First, we set up a vector of numbers. Then we count them using the table() command, and then we plot them. The table()…